1. Field of the Invention
The present invention pertains to the field of portable computing devices. More particularly, the present invention relates to testing batteries to determine whether power should be supplied to particular components when an attempt is made to fully or partially enable or otherwise increase the power consumption of the system.
2. Description of Related Art
Many portable computing or other electronic devices are powered by batteries. Inevitably, unless charged, such batteries discharge and are no longer able to maintain operation of their host device. Users, however, often attempt to turn on their portable electronic devices either because they are unaware of the fact that the batteries are discharged or in an attempt to obtain additional operation from the failing batteries.
Unfortunately, failing batteries may cause problems for some electronic devices. For example, some electronic devices contain components which do not function properly when insufficient power is supplied. As a result, certain operations may be performed inaccurately and/or data may be corrupted. Even worse, other components may be damaged when insufficient battery power is available.
In general, some prior art devices detect and react to low battery power. In particular, prior art portable computer systems often utilize hardware such as a System Management Controller (SMC) which communicates with various system batteries and components over a System Management Bus (SMBus) to manage power consumption. Further details regarding the SMBus protocol are available in the SMBus Specification, Revision 1.0, Feb. 15, 1995, available from the Smart Battery System Implementer's Forum (on the Internet at the time of filing of this application at www.sbs-forum.org).
Prior art computer systems typically only monitor batteries during normal operation. Such systems use the SMBus or other power control hardware in warning the user of low battery power and/or shutting down the system if needed. Additionally, some systems switch between primary and secondary battery supplies during normal operation and even temporarily resort to using a back-up battery to shut down the system in an orderly fashion to avoid the loss of data.
The prior art does not, however, provide a technique which performs a pre-check of battery levels. That is, the prior art does not test power levels of the batteries which would otherwise supply power to electronic components before such batteries are allowed to power such electronic components. Consequently, it would be possible for an improperly charged (i.e., overcharged or undercharged) battery to damage such components.